Field
The present invention relates to a fingerprint detection device and a driving method therefor, and more particularly, to a fingerprint detection device improved in a detection operation speed and a detection accuracy, and a driving method thereof.
Discussion of the Background
Since a pattern of a fingerprint varies from person to person, it has been widely used in a personal identification field. Specifically, as a personal verification means, a fingerprint has been widely used in a variety of fields including banking, criminal investigation, security and the like.
A fingerprint recognition sensor has been developed to recognize such a fingerprint, thereby identifying a person. The fingerprint recognition sensor is a device for recognizing a fingerprint of a person by coming in contact with a finger thereof, and is utilized as a means for determining whether or not a person has a proper right.
A fingerprint detection device, which recognizes a feature of each area of a fingerprint to obtain a fingerprint image, includes a sensor array configured with a plurality of fingerprint sensor elements provided in a form of a matrix.
The plurality of fingerprint sensor elements come in contact with some portion of a finger, and generate different signals according to whether some portion of the finger being currently contacted is a ridge or a valley thereof. In particular, a driving signal is applied to a finger, and the fingerprint sensor element generates a different response signal depending on a portion of the finger coming in contact with the fingerprint sensor element.
Meanwhile, noise due to an external environment or induced by an internal configuration of a fingerprint detection device or the like may be included in output signals from the plurality of fingerprint sensor elements. In order to eliminate such noise, the output signal from each of the fingerprint sensor elements is transmitted to a filter and buffer unit.
Currently, when the plurality of fingerprint sensor elements are arranged in a form of N×M matrix, a scan operation with respect to the fingerprint sensor elements from a first column to an M-th column, that is, a fingerprint detection operation is sequentially performed, and an output signal from the fingerprint sensor element corresponding to each column is sequentially transmitted to the filter and buffer unit.
In other words, an output signal acquisition from the plurality of fingerprint sensor elements sequentially proceeds from the first column to the M-th column. If the number of columns of the sensor array is increased, a time required for performing a fingerprint detection operation at once with respect to all the fingerprint sensor elements should be increased.
In addition, according to the current method described above, an output signal acquisition from the fingerprint sensor elements arranged at an adjacent column is consecutively performed. In other words, after the output signal acquisition from the fingerprint sensor elements arranged at the first column is completed, an output signal acquisition from the fingerprint sensor elements arranged at a second column adjacent to the first column is consecutively performed. When the fingerprint detection operation with respect to a fingerprint sensor element is performed, an electrical signal flows at the fingerprint sensor element and this may be a cause for forming a parasitic capacitance and the like in interaction with a neighboring fingerprint sensor element. That is, the neighboring fingerprint sensor element would be electrically affected by the fingerprint detection operation with respect to the fingerprint sensor element. Therefore, when the fingerprint detection operation with respect to the neighboring fingerprint sensor element is proceeds consecutively, a fingerprint detection may be largely affected by an external environment to cause a degradation of accuracy of the fingerprint detection.
Consequently, a fingerprint detection device capable of improving not only accuracy of a fingerprint detection but also a speed thereof may be needed.